DBS-C01 Workload-Specific Database Design Practice Question
A company is migrating a self-managed MongoDB database to Amazon DocumentDB. The database stores user profiles and activity logs. The activity logs are write-heavy and accessed infrequently. The company wants to optimize cost and performance for the workload. Which THREE design decisions should the company make?
⚠ Common exam trap
Many candidates assume a single cluster with read replicas is sufficient for mixed workloads, but the exam tests the understanding that separate clusters are needed to isolate write-heavy and read-heavy workloads for cost and performance optimization.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable encryption at rest for both databases.
Enabling encryption at rest for Amazon DocumentDB is a security best practice that ensures data is encrypted using AWS Key Management Service (KMS) keys. This is a mandatory design consideration for compliance and data protection, and it does not significantly impact cost or performance for the workload described.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable encryption at rest for both databases.
Why this is correct
Encryption at rest is a security best practice.
- ✓
Use a t3.medium instance for the activity logs collection to reduce cost.
Why this is correct
A smaller instance is appropriate for infrequently accessed data.
- ✗
Use Amazon S3 for storing activity logs instead of DocumentDB.
Why it's wrong here
Activity logs are accessed infrequently but still require querying; S3 is not suitable for document queries.
- ✓
Create separate DocumentDB clusters for user profiles and activity logs.
Why this is correct
Separating workloads allows independent scaling and performance tuning.
- ✗
Use a single DocumentDB cluster for both workloads with appropriate read replicas.
Why it's wrong here
Mixing different workloads can cause performance interference.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.